Extrasynaptic membrane trafficking regulated by GluR1 serine 845 phosphorylation primes AMPA receptors for long-term potentiation

Michael C. Oh, Victor A. Derkach, Eric S. Guire, Thomas R. Soderling

    Research output: Contribution to journalArticle

    333 Scopus citations

    Abstract

    Enhancement of synaptic transmission, as occurs in long-term potentiation (LTP), can result from several mechanisms that are regulated by phosphorylation of the AMPA-type glutamate receptor (AMPAR). Using a quantitative assay of net serine 845 (Ser-845) phosphorylation in the GluR1 subunit of AMPARs, we investigated the relationship between phospho-Ser-845, GluR1 surface expression, and synaptic strength in hippocampal neurons. About 15% of surface AMPARs in cultured neurons were phosphorylated at Ser-845 basally, whereas chemical potentiation (forskolin/rolipram treatment) persistently increased this to 60% and chemical depression (N-methyl-D-aspartate treatment) decreased it to 10%. These changes in Ser-845 phosphorylation were paralleled by corresponding changes in the surface expression of AMPARs in both cultured neurons and hippocampal slices. For every 1% increase in net phospho-Ser-845, there was 0.75% increase in the surface fraction of GluR1. Phosphorylation of Ser-845 correlated with a selective delivery of AMPARs to extrasynaptic sites, and their synaptic localization required coincident synaptic activity. Furthermore, increasing the extrasynaptic pool of AMPA receptors resulted in stronger theta burst LTP. Our results support a two-step model for delivery of GluR1-containing AMPARs to synapses during activity-dependent LTP, where Ser-845 phosphorylation can traffic AMPARs to extrasynaptic sites for subsequent delivery to synapses during LTP.

    Original languageEnglish (US)
    Pages (from-to)752-758
    Number of pages7
    JournalJournal of Biological Chemistry
    Volume281
    Issue number2
    DOIs
    StatePublished - Jan 13 2006

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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